Powder actuated tool



Feb. 10, 1970 0. L. ROB INSON POWDER ACTUATED TOOL 2 Sheets-She t 1Filed June 24, 1968 DALE L. ROBINSON INVENTOR BUG/(HORN, BLORE,KLAROU/ST 8 SPAR/(MAN ATTORNEYS Feb. '10, 1970 o. L. ROBINSON 3,4 POWDERACTUATED TOOL Filed June 24, 1968 2 Sheets-Sheet 2 FIG. 4

DALE L ROBINSON INVENTOR BUC/(HOR/V, BLORE, KLAROU/ST 8 SPAR/(MAN 47' 7'OR/VE KS United States Patent 3,494,125 POWDER ACTUATED TOOL Dale L.Robinson, Portland, 0reg., assignor to Omar-k Industries, Inc.,Portland, Oreg., a corporation of Oregon Filed June 24, 1968, Ser. No.739,392 Int. Cl. F011) 29/08; B25c 1/12, N14

US. Cl. 6026.1 13 Claims ABSTRACT OF THE DISCLOSURE A captive pistontype of powder actuated tool is provided with a barrel pivotally engagedby the forward end of the tool housing so that the breech end of thebarrel can be upraised into a loading position. An elongatedhandle-operated sleeve is slidably carried on the barrel andsubstantially covers the barrel. This sleeve includes a piston retractorportion provided with means extending through a slot in the barrel forengaging the head of the piston, and by means of which the piston isreturned to an operative position after firing. The piston-returnoperation is accomplished by pulling the sleeve rearwardly partially otfthe barrel. The barrel can be pivotally returned to its normal position,in alignment with the tools breech-block, only after the sleeve has beenmoved forwardly out of the way of the breech-block. Such forward returnof the sleeve clears the piston retractor mechanism from the firing pathof the piston.

BACKGROUND OF THE INVENTION Piston type explosive actuated tools, e.g.for driving fastener devices into concrete or masonry walls,conventionally employ a blank cartridge for providing the explosivegases applied to drive the fastener device. Such a tool is cocked bypressure of the muzzle against a workpiece or wall, resulting inmovement of the tools breechblock into a firing position. The cartridgemay then be fired to force the captive piston through the barrel fordriving the fastener device. After firing, the barrel and thebreech-block are separated so that a new cartridge or power load may beinserted, and the captive piston must be returned to its firingposition. Various constructions have been employed heretofore tofacilitate the loading and piston return operations. The barrel may berotated laterally to the side of the tool facilitating removal of thecaptive piston to a firing position and insertion of a new load.Alternatively, the barrel may be movable longitudinally forward of thetool for retraction of the piston and reloading. In the case of theseconstructions and other similar ararngements, the tool mechanism is aptto be quite complex and/ or somewhat unbalanced.

In the copending application 737,900 of Raymond V. Pomeroy, filed June18, 1968, assigned to the assignee of the present invention, there isdisclosed and claimed a powder actuated tool of the captive piston typewherein the breech end of the barrel may be pivoted away from the toolsbreech-block into a loading position. The tool of the Pomeroyapplication further includes a piston retractor slidably carried by thebarrel for moving the captive piston into a firing position. The tool isof compact and balanced construction, and is easy to handle and tooperate, as well as being economical to manufacture. In the Pomeroytool, however, the tools barrel is for the most part exposed, and it hasbeen found that a tool of this type can be cocked against a workpiece orwall and then retained in a cocked position by grasping the barrel, whenthe tool may no longer be in engagement with a wall or workpiece. As aresult, it is sometimes possible to fire the tool improperly or in anunsafe manner.

Furthermore, location of the piston retracting handles "ice in the toolof the aforementioned application, close to the muzzle end of the tool,requires the tools operator to reach farther in retracting a piston thanin performing other tool operations.

SUMMARY OF THE INVENTION According to the present invention a powderactuated tool comprises a housing including a rearward breech portionand a forward barrel portion. The tools barrel is cradled by the barrelportion when the barrel is in a first position in substantial alignmentwith the tools breech-block. The barrel is pivotally engaged by thebarrel portion at a forward location so that the breech end of thebarrel can be pivotally upraised away from the breech-block into aloading position. The tool further comprises a sleeve slidably enclosingthe barrel, the sleeve including a retractor means for engaging thepiston, and a rearward handle which is manually engageable for movingthe piston retractor means. The piston may be moved thereby to a firingposition toward the breech end of the barrel. When the sleeve is movedfor positioning the piston in its firing position, the sleeve extendsbeyond the tools breech-block, preventing closure and firing of the tooluntil the sleeve is once again moved forwardly for placing the retractormeans out of the way of the pistons travel during firing. The sleevesubstantially covers the barrel and prevents retention of the tool in acocked position when the same is not urged against a workpiece. Also,rearward placement of the handle at the breech end of the sleeveadjacent the tools breech-block enhances the ease of operation of thetool.

It is accordingly an object of the present invention to provide animproved powder actuated tool of the captive piston type which is Wellbalanced, compact, and easily manufactured.

It is a further object of the present invention to provide an improvedpowder actuated tool of the captive piston type which is safer and moreconvenient in operation.

The subject matter which I regard as my invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. The invention, however, both as to organization andmethod of operation together with further advantages and objectsthereof, may best be understood by reference to the followingdescription taken in connection with the accompanying drawings whereinlike reference characters refer to like elements.

DRAWINGS FIG. 1 is a longitudinal cross section of a powder actuatedtool according to the present invention;

FIG. 2 is a lateral cross section of the FIG. 1 tool taken at 2-2 inFIG. 1;

FIG. 3 is a lateral cross section of the FIG. 1 tool taken at 33 in FIG.1;

FIG. 4 is a top view partially broken away in horizontal cross sectionof the FIG. 1 tool; and

FIG. 5 is a side view of the FIG. 1 tool in a loading position thereof.

DETAILED DESCRIPTION Referring to the drawings, an explosively operatedtool includes a housing generally indicated at 10 including a forwardportion 12 which may be designated as a barrel portion and a rearwardportion 13 which may be designated as a breech portion. Rearward portion13 includes a handle portion or grip 118. Barrel portion 12 issemicircular in cross section and cradles barrel 14 received withinsleeve 17 when the barrel is in a first position. In this firstposition, the barrel is aligned with the breechblock 16, the latterbeing located in the breech portion of the housing. Sleeve 17 is metaland extends over the barrel substantially along the barrel portion ofthe housing when the barrel is aligned with the breechblock.

Barrel 14 is cylindrical and extends from muzzle 15 rearwardly to apower plug 18 received in the breech end of the barrel. The barrel isprovided with an inner bore 20 within which a captive piston 22 isslidable, such piston having an enlarged piston head 24 which slidesalong inner bore 20, and a ram or plunger 26 adapted to contact anddrive the head of a fastener device (not shown) into a workpiece at theleft end of muzzle 15. Enlarged head 24 of the captive piston includes arearward head portion and a forward head portion 27 slidably engagedwith the inside of the barrel bore. Head portion 25 is suitably providedwith a piston ring or seal 32 therearound to prevent excessive escape ofgas past head 24. Power plug 18 is threadably received in the breech endof the barrel, power plug 18 including a chamber 36 for receiving apower load or cartridge.

Breechblock 16 is longitudinally slidable within breech portion 13 ofthe housing and is recessed at 38 to receive power plug 18 in the firingposition thereof. Breechblock 16 slidably carries firing pin holder 40,in turn carrying a tapered firing pin 42. The firing pin holder isnormally held in a retracted position relative to breechblock 16 by sear44 which is urged at this time by spring 46 to a location adjacent anedge 48 of the breechblock. When the tool is cocked and the breechblockis forced to the right into a cocked position against the spring bias ofsprings 50 and 52, sear 44 will be aligned with trigger bar 54 and canbe moved upwardly by trigger bar 54. When breechblock 16 is in suchcocked position, firing pin spring 56 is compressed, and upward movementof the sear 44 causes tapered firing pin 42 to be driven by spring 56into tapered bore 58 in the breechblock 16. The firing pin 42 is adaptedto project through tapered bore 58 and strike a rim fire power load orthe like positioned in chamber 36. To fire the tool, trigger 60 iscompressed against spring 62 moving trigger bar 54 upward into contactwith sear 44, providing the latter is in cocked position. Trigger bar 54is carried in a vertical slot in the trigger and is pivoted at 57, beingmaintained in alignment with the trigger by internal springs 59. Thismechanism permits the trigger bar 54 to turn in a clockwise mannerwithout damage in the event that the tool is cocked with the triggercompressed. In this event, trigger bar 54 will merely rotate in aclockwise sense as the side of sear 44 contacts the same. The tool maythen not be fired until the trigger is released and compressed again.

. The barrel portion 12-of the housing, being semicircular in crosssection, is substantially channel-shaped and open upwardly where itreceives or cradles cylindrical barrel 14, as enclosed in sleeve 17,when the barrel is in a first position in alignment with breechblock 16.The barrel 14 is pivotally engaged by the barrel portion 12 of thehousing at a location toward the muzzle end of the barrel so that thebreech end of the barrel can be upraised away from the breechblock intoloading position. Pin member is carried by the barrel substantially atthe aforementioned location toward the muzzle end of the barrel, pinmember 120 extending vertically from the lower side of the barrel Whereit is received in a longitudinal slot 122 in barrel portion 12 of thehousing. Pin member 120 can move between the left hand end wall of slot122, as viewed in FIG. 1, and horizontal roll pin 124 carried in thebarrel portion 12 of the housing, pin 124 in effect defining the rightend of slot 122. Pin member 120 thereby permits longitudinal slidingmovement of the barrel for full engagement of power plug 18 withinrecess 38 of breechblock 16, as well as movement of the breechblock 16within breech portion 13 of the housing into the aforementioned cockedposition. As viewed in FIG. 1, the barrel may thus be moved to the leftso that power plug 18 no longer engages breechblock 16, or the barrelmay be moved to the right into a fully cocked position, compressingbreechblock 16 against the bias of springs 50 and 52 until sear 44 isover trigger bar 54. In the cocked position of the tool, barrel 14, aswell as sleeve 17, extend within breech portion 13 of the housing. Fordisassembly of the tool, roll pin 124 may be removed permitting theupraised barrel (as illustrated, for example, in FIG. 5') to beWithdrawn upwards and to the right, since horizontal pin 124 no longerblocks passage of vertical pin member 120.

The barrel portion 12 is provided with an arched barrel retaining member68 proximate and above the location of pin member 120. The arched barrelretaining member 68 has an inner surface 70 semicircular in crosssection which substantially matches the cylindrical barrel 14, but whichis angled upwardly and to the right in FIG. 1. It will be apparent thatbarrel 14 may be moved to the left whereby power plug 18 clearsbreechblock 16, and then the breech end of the barrel may be movedupwardly into a loading position (as seen in FIG. 5), with the barrelpivoting at its forward end. At this time, arched barrel retainingmember 68 limits the upward movement of the barrel, and when barrel 14is upraised as far as it will go, the inner surface 70 of the retainingmember substantially matches or cradles the upper side of barrel 14 andsleeve 17.

The barrel 14 is provided with a longitudinal slot 72 on the undersidethereof or the side toward barrel portion 12 of the housing. Thislongitudinal slot does not extend the full length of the barrel,butstops short of the breech and muzzle ends thereof as illustrated.Thus, ring 32 on piston head 24 is located a predetermined distancetoward power plug 18 from the breech end of slot 72 in the firingposition of the piston. Also, the muzzle end of ,slot 72 is proximate aninsert or stop 74 located at the left end or muzzle end of barrel 14.

Sleeve 17 substantially encloses the barrel along the barrel portion ofthe housing from the breechblock to the location where the barrel ispivotally engaged, assuming the barrel is in alignment with breechblock16 as illustrated in FIG. 1. To be more exact, the sleeve 17, whichincludes a retractor portion 76, extends from horizontal pin 124 toslightly beyond the breech end of barrel 14, When the tool is in theposition illustrated in FIG. 1. When the tool is cocked by depressingmuzzle 15 against a workpiece, wall, or the like, the sleeve, of course,moves rearwardly as sear 44 becomes positioned over trigger bar 54.

The sleeve 17 is provided with a handle 78, suitably formed of plastic,positioned at a location close to the breech end of sleeve 17. Handle 78is semicircular in configuration as illustrated in FIG. 3 for fittingaround the upper portion of sleeve 17. An internally threaded metalinsert 126 is brazed to sleeve 17, and handle 78 is provided with amatching vertical bore for receiving insert 126. The upper portion ofthe vertical bore in handle 78 is countersunk to match the head ofsecuring screw 128 which holds handle 78 against sleeve 17. In addition,handle 78 is also desirably adhered to metal sleeve 17 with a suitableplastic-to-metal bonding material.

As has been mentioned, in its normal position sleeve 17 extends fromwhere the barrel is pivotally engaged to a location proximate the breechend of the barrel. The positioning of handle 78 at approximately thelatter location gives the operator of the tool more convenient or closeraccess to a handle for retracting the captive piston, 22, and provides adirect pull on the captive piston during the retracting operation.

In barrel portion 12 of the housing, substantially under handle 78,there is located a magnet 130 normally held in position by a horizontalpin 132 extending through the magnet and into the housing. The purposeof this magnet is to attract and normally hold the sleeve 17 carryingthe barrel so that the sleeve and barrel will not pivot away from thehousing unless such action is desired. Thus, magnet 130 normally securesbarrel 14 in its position shown in FIG. 1, unless the barrel is to beupraised, e.g. by means of handle 78.

The sleeve 17 includes piston retractor portion 76 carried by the barrelat the muzzle end of the sleeve. This piston retractor portion comprisesa ring, slidably mounted on the exterior of the cylindrical barrel, thering being joined to or unitary with the remainder of sleeve 17.Retractor portion 76 includes a member 82 comprising a dog for engagingpiston head portion 27 as when the piston 22 has moved toward the muzzleend of the barrel. As illustrated in FIG. 5, barrel 14 may be pivotallyupraised by pivoting around its forward location, after which the sleeve17 may be moved to the right by means of handle 78 to slide retractorportion 76 to the right. Member 82 engages head portion 27 as retractorportion 76 is moved to the right, bringing with it piston 22 until thepiston is returned to the right end or breech end of barrel 14. Then,sleeve 17 including retractor portion 76 is moved to the left-handposition illustrated in the drawings, and indeed must be before barrel14 can be returned to a position in alignment with power plug 18. Sleeve17 in its extended position, as indicated by broken lines in FIG. 5,extends beyond breechblock 16, and the breech portion 13 of the housing,preventing return of barrel 14 to its firing position. Moreover, thebarrel portion of the housing includes wedge-shaped recess 92 forreceiving a lower wedge-shaped portion 94 of the retractor portion onlywhen the retractor portion is returned to its left-hand position. It isnoted the retractor portion 76 is always removed out of the way of themovement of piston 22 when the tool is in firing position, therebyavoiding danger to the operator of the tool from undesired movement ofretractor portion 76 and sleeve 17 when the tool is fired.

Lower wedge-shaped portion 94 of retractor 76 carries member 82 in avertical slot 96 at the middle thereof, with the L-shaped member 82being secured in the slot at its rearward end by means of horizontal pin98 and at its forward end by horizontal pin 100. Wedge-shaped portion 94is prevented from moving forward of its position in FIG. 1 relative tothe barrel portion of the housing, i.e. when the tool is in an uncockedposition, by means of horizontal pin 124. Horizontal pin 124 thus actsas a forward stop for barrel 14 and sleeve 17.

When the tool is fired, a power load explodes and combustion explosiongases enter bore 20 of barrel 14 forcing piston 22 to the left. As headportion 25 moves past the breech end of slot 72, these gases are ventedalong slot 72 within sleeve 17 and leave around retractor portion 76.Sleeve 17 suitably encloses barrel 14 circumferentially therearoundcompleting a muffler enclosure acting to reduce the audible reportproduced by firing the tool.

Piston 22 is provided with an ejector 86 which may protrude into chamber36 for ejecting power load or cartridge 88. The ejector 86 is tapered atits rearwardmost end. This tapered configuration acts to guide explosiongases along the chamber with minimum lateral deflection of such gasesduring firing of the tool to prevent chamber erosion. This constructionis more fully described in the copendrrng application of Yung Shing Hsuentitled, Chamber Erosion Preventing Powder Actuated Tools, Ser. No.675,140 filed Oct. 13, 1967, and assigned to the assignee of the presentinvention.

The captive piston 22 is tapered between head 24 and ram or plunger 26,and this tapered portion and head 24 have a low hardness and highductility as compared with a high hardness and little or no ductility ofstop 74. The hard metal stop 74 includes a long cylindrical entrancebore 114 and a frustoconical die portion 116. The bore 114 serves toslidably receive the muzzle end of the piston head 24, to the left ofhead portion 27, should the captive piston 22 be overdriven so that ram26 extends outwardly at the left of muzzle 15. Should the piston thus beoverdriven, piston energy is dissipated by extruding, by frustoconicaldie portion 116, the tapered portion of the captive piston 22. Theconstruction allows the dissipation of energy of an overdriven pistonwithout damage to the captive piston inasmuch as bore 114 laterallysupports the captive piston during overdriving so as to prevent bendingof the piston. This energy-dissipating mechanism is further describedand claimed in the copending application 796,980 of Yung Shing Hsu andRaymond V. Pomeroy, filed Feb. 6, 1969 and assigned to the assignee ofthe present invention.

In the general operation of the tool according to the present invention,a fastener device is inserted in muzzle 15, and the user grasps a handleportion or grip 118 and forces the fastener device against a workpiecesuch as a masonry wall or the like. Urging the tool against a workpiecebrings about full contact between power plug 18 and breechblock 16, andfurther urges the breechblock rearwardly of the tool into a cockedposition, i.e. placing sear 44 above trigger bar 54. The trigger 60 maynow be compressed raising sear 44 such that firing pin 42 is driven tothe left exploding a cartridge or other power load in chamber 36.Explosive gases enter the inner bore of barrel 14 behind the head 24 ofthe captive piston driving the captive piston to the left and forcingthe fastener device into the workpiece. As hereinbefore mentioned,explosive gases leave through slot 72 as the head portion 25 passes thebreech end of slot 72 from what may be considered a combustion chamberinside the barrel to the right of slot 72 in FIG. 1. These gases leavedirectly through the length of slot 72 within sleeve 17. It should benoted the tool cannot be cocked against a workpiece and then removedfrom the workpiece, with the barrel being manually held in a cockedposition, because the major portion of the barrel is substantiallyinaccessible within sleeve 17 To reload the tool, and return the captivepiston to firing position, the barrel is moved to the left as bygrasping muzzle 15, and the breech end thereof is pivoted upwardly byraising the same with handle 78. In practice, the tool may also begrasped by grip 118 and snapped in a downward direction causing thebarrel 14 to lower and pivot so that the breech end of the barrelincluding power plug 18 tilts away from the breechblock. With the barrelin the out-tilted position, handle 78 mounted on sleeve 17 is graspedand pulled rearwardly. As a result, member 82 engages the outer edge ofhead portion 27 pulling the piston 22 to the right, back to a firingposition. The movement of the piston, as head portion 25 reaches thebreech end of slot 72, may force shell or power load 88 from chamber 36.If ejection is not accomplished by air pressure, the ejector contactsthe cartridge for forcibly removing the same. Rearward movement ofsleeve 17 and barrel 14 is limited by contact of member 82 against headportion 27 of the completely retracted piston. The sleeve and retractorportion are then returned to their forwardmost position by means ofhandle 78, and a new cartridge or power load is inserted in chamber 3-6.The barrel 14 is then pivoted back into alignment with breechblock 16for the next operation. It is seen that the operation of the toolaccording to the present invention is simple, and construction thereofis compact. Since the weight of the tool is well balanced, the tool iseasy to handle.

The enclosure of the barrel 14 in sleeve 17, extending substantiallyalong the barrel portion of the housing, prevents retention of the toolin a cocked position when the same is not being urged against aworkpiece. Thus, since the barrel is covered, it is substantiallyimpossible to force the muzzle against a workpiece and then remove themuzzle from a workpiece while manually holding the barrel in cockedposition. Therefore, accidental or intentional firing of the tool, otherthan into a solid workpiece or the like, is avoided.

Moreover, the elongated sleeve locates handle 78 toward the breech endof the tool, permitting easier access to the handle for retracting thecaptive piston from its fired to its firing position. This location ofthe handle not only provides for more convenient operation, but also hasbeen found to enable a more satisfactory longitudinal retracting pull onthe captive piston. Less force is frequently required because lessbinding can take place as compared with an instance where retractinghandles are located at the side or toward the muzzle end of the tool.

The construction of the tool according to the present inventionemploying a sleeve surrounding the barrel also provides a simple andefficacious means of preventing the repositioning of the barrel inalignment with the breechblock until the piston retractor is returned toits forward position. That is, the sleeve 17 simply extends beyond thebreechblock until the retractor portion is returned to a location out ofthe normal path of captive piston 22.

It should be noted that when the tool is urged against a workpiece,retractor portion 76 is automatically urged to the rear of wedge-shapedrecess 92, assuming the retractor portion 76 is not already in suchposition. With the tool forced against a workpiece, the retractorportion 76 is held in position between the breech end of recess 92 andthe muzzle end of slot 72. The muzzle end of slot 72 engages theinwardly extending portion of member 82. Therefore, when the tool isfired, no undesired movement of retractor portion 76 or sleeve 17 willtake place. It should be noted that even if the piston 22 should beoverdriven into stop 74, the edge of head portion 27 will not strike ormove member 82, when the retractor portion 76 is in its locked positionbetween the edges of recess 92 and slot 72.

- I claim:

1. In a powder actuated tool including a housing, a breechblock carriedby a breech portion of the housing, a barrel supported in cradledrelation by a barrel portion of the housing when said barrel is in afirst position in substantial alignment with said breechblock, a captivepiston longitudinally slidable within said barrel, and a pistonretractor for moving said piston to a firing position toward the breechend of said barrel, said barrel being pivotally engaged by the barrelportion of said housing at a location toward the muzzle end of saidbarrel so that the breech end of said barrel can be upraised away fromsaid breechblock into a loading position,

the improvement comprising:

sleeve means slidably carried by said barrel and extending, when saidbarrel is in a first position in substantial alignment with saidbreechblock, substantially from said breechblock to said location wheresaid barrel is pivotally engaged,

said piston retractor comprising a portion of said sleeve means towardthe muzzle end of said sleeve means,

and handle means carried by said sleeve means proximate the breech endof said sleeve means for sliding said sleeve means partially off thebreech end of said barrel to move said piston retractor and piston intosaid firing position.

2. The tool according to claim 1 wherein said barrel is provided with alongitudinal slot ending short of the breech and muzzle ends of saidbarrel, and wherein said piston retractor includes means extendingthrough said longitudinal slot in said barrel for engaging the head ofsaid piston at the muzzle end thereof.

3. The tool according to claim 1 wherein said sleeve means substantiallyencloses said barrel as said barrel is cradled in supporting relation bysaid housing, said sleeve means being coaxially interposed between saidbarrel and the barrel portion of said housing.

4. The tool according to claim 1 including a substantially vertical pinmember carried by said barrel at said location toward the muzzle end ofsaid barrel, said pin extending from the lower side of said barrel,

the barrel portion of the housing being provided with a longitudinalslot means through which said vertical pin member extends, saidlongitudinal slot means having an effective length permittinglongitudinal sliding movement of the barrel from nonengagement to fullengagement with the breechblock plus rearward movement of thebreechblock into a cocked position.

5. The tool according to claim 4 including a horizontal pin normallytransversely positioned in the barrel portion of said housing foreffectively defining the rearward extent of said longitudinal slot meansand the longitudinal movement of said barrel,

said horizontal pin being removable for disassembly of said tool,permitting movement of said vertical pin upward and outward to the rearof said tool.

6. The tool according to claim 2 wherein said barrel portion of thehousing is semicircularly channel-shaped and open upwardly,

said barrel portion of the housing being provided with an arched barrelretaining member proximate said location toward the muzzle end of thebarrel for substantially enclosing the upper side of the barrel at suchlocation,

said arched barrel retaining member having an inner semicircular surfacefor substantially matching the barrel in an upraised position thereofand for limiting the upward movement of the barrel.

7. The tool according to claim 2 wherein said sleeve means substantiallyencloses said barrel from said breechblock to said location where saidbarrel is pivotally engaged, at a time when said barrel is in a firstposition in substantial alignment with said breechblock, saidlongitudinal slot in said barrel as closed by said sleeve means forminga muflier enclosure for said tool acting to reduce the audible reportproduced by firing the tool as explosion gases pass along said slottoward the piston retractor.

8. The tool according to claim 1 wherein said barrel portion of thehousing below the handle means carried by the sleeve means is providedwith a magnet secured to the housing for attracting and removablyholding said sleeve means when said barrel is in said position insubstantial alignment with said breechblock.

9. A powder actuated tool comprising:

a housing including a rearward breech portion and a forward barrelportion,

a breechblock carried by said breech portion,

an elongated barrel supported by the barrel portion of said housing,

a sleeve slidably carried on said barrel along the barrel portion ofsaid housing and extending substantially to said breechblock, when saidbarrel is in a first position in substantial alignment with saidbreechblock, said sleeve being cradled by said barrel portion of saidhousing,

said barrel being pivotally engaged by the barrel portion of saidhousing at a location toward the muzzle end of said barrel so that thebreech end of said barrel and the sleeve carried thereby can be upraisedaway from said breechblock into a loading position, a captive pistonlongitudinally slidable within said barrel and movable in response toexplosion of a power load for driving a fastener element into aworkpiece at the muzzle end of said barrel,

said sleeve including a piston retractor portion slidably carried bysaid barrel and normally located at the muzzle end of the barrel, saidretractor portion including a member for engaging said piston, and

a handle means mounted on said sleeve and manually engageable for movingsaid piston retractor and said piston to a firing position toward thebreech end of said barrel when said barrel and sleeve are upraised awayfrom said breechblock.

10. The tool according to claim 9 wherein said sleeve substantiallyencloses the barrel approximately between said breechblock and saidlocation where the barrel is pivotally engaged.

11. The tool according to claim 9 wherein the said 9 10 handle means issecured on the upper side of said sleeve means for providing relativemovement between said proximate the breech end of said sleeve. barreland breechblock so that said sleeve is movable 12. A powder actuatedtool comprising: past said breechblock to move said piston to a firing ahousing including a rearward breech portion and a position toward thebreech end of said barrel.

13. The tool according to claim 12 wherein said handle means is locatedproximate the breech end of said sleeve.

forward barrel portion,

a breechblock carried by the breech portion,

a barrel carried by the barrel portion, said barrel slidably carrying asleeve substantially enclosing a maferences C ed jor portion of saidbarrel and normally extending sub- UNITED STATES PATENTS stantially tothe position of said breechblock, 1 a captive piston longitudinallyslidable within said barg i 2 rel and movable in response to explosionof a power emp 6 et a load for driving a fastener element into aworkpiece 3172119 3/1965 Siddons 227 8 at the muzzle end of Said barrel3,357,617 12/1967 Osborne 227-10 3,409,197 11/1968 Brack 227-10 saidsleeve including piston retractor means for engag- 15 ing said pistonwithin said barrel and returning the same to a firing position towardthe breech end of WENDELL BURNS Pnmary Exammer said barrel, C1 R handlemeans mounted on said sleeve and manually engageable for moving saidpiston retractor means and said piston, and

